1、 Different materials
1. Five sided mirror: it uses specular reflection. The specular reflection uses a silver plated surface. There must be light loss.
2. Pentaprism: it is formed by cutting and grinding a whole solid glass, and then the outer surface (except the two surfaces connected with the focusing screen and the viewfinder eyepiece) is coated with reflective materials to form specular reflection inside.
2、 Different characteristics
1. Pentahedral mirror: the advantage of pentahedral mirror as the viewfinder of SLR is that it is conducive to reducing the weight of the camera, and the cost is relatively low compared with pentaprism, so it is used in some popular SLR cameras.
2. Pentaprism: it is a reflective device for SLR camera. Its function is to correct the left and right inverted images on the focus screen, so that the image seen in the view is completely consistent with the orientation of the directly seen scene, so that the operator can correctly view and focus.
3、 Different reflection
1. Pentahedral mirror: pentahedral mirror can only achieve 80% brightness of pentaprism.
2. Pentaprism: total reflection, no light loss at all. So a pentaprism must be brighter than a pentahedral mirror.
